Disk Brake Internal Gear Positioning With Single Rotation Restriction
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Solution Overview
Problem
The conventional planetary gear speed reduction mechanism in disk brakes faces issues with positional variation of the internal gear due to irregular formation of rotation prohibition portions, leading to increased costs and potential effects on gear strength, actuation noise, and backlash.
Innovation Solution
A disk brake design that incorporates a planetary gear speed reduction mechanism with a rotation restriction portion between the internal gear and the support member, positioned perpendicular to the straight line connecting the radial centers of the first and second gears, allowing for improved positional precision and reduced cost by optimizing the fit dimensional tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If rotation prohibition portions are formed at four positions circumferentially between the internal gear and housing, then the internal gear position precision is improved, but the manufacturing cost increases due to reduced dimensional tolerances
Solution Approach 1:
The invention extracts the rotation prohibition function from multiple distributed portions and concentrates it into a single rotation prohibition portion. This single portion is positioned at a specific location where the straight line connecting the radial centers of the first and second speed reduction gears is perpendicular to the rotation prohibition portion. By taking out the function from four positions and concentrating it to one position, the manufacturing cost is reduced while maintaining the internal gear position precision.
2Manufacturing precision
If fit dimensional tolerances are reduced for rotation prohibition portions, then the variation in internal gear position is reduced, but the manufacturing complexity and cost increase
Solution Approach 1:
The invention extracts the rotation prohibition function from multiple portions with complex dimensional tolerance requirements and concentrates it into a single rotation prohibition portion. This single portion is strategically positioned where the straight line connecting the radial centers of the first and second speed reduction gears is perpendicular to the rotation prohibition portion. By concentrating the function, the number of dimensions requiring tight tolerance management is reduced, thereby simplifying the device complexity while maintaining position precision.
Data Source
AI summary
A disk brake that includes, between an internal gear (69) and a first housing portion (19) of a housing (18), each of protrusion portions (105) provided on the internal gear side and engagement recessed portions (44) provided on the first housing side that are engaged with each other to restrict a relative rotation. Each of these protrusion portions on the internal gear side and engagement recessed portions on the first housing portion side are disposed along a direction perpendicular to a straight line connecting a radial center of a second speed reduction gear (67) and a radial center of a first speed reduction gear (54). Due to this configuration, the disk brake can improve the precision of the position of the internal gear of the planetary gear speed reduction mechanism (27) while reducing the cost.